1. Field of the Invention
For example, in a communication system such an automobile or portable telephone system and a radio LAN, a CDMA (Code Division Multiple Access) communication using a spread spectrum system is practiced particularly.
2. Description of the Related Art
In the case of a third generation W (wideband)-CDMA system, BCH (Broadcast Channel) information in a transport channel is transmitted using a P-CCPCH (Primary Common Control Physical Channel) in a physical channel by a 3GPP standard. It is considered that the P-CCPCH forms one piece of CRC (Cyclic Redundancy Check) information using P-CCPCH data of two frames for information transmission efficiency.
A GAP (time interval) of several slots during reception of a base station signal currently in the midst of telephone communication is provided, and a compressed Mode, which is a function to search a base station having a different frequency f2 from a base station frequency f1 by using this GAP, has been proposed.
In the case of the third generation W-CDMA system, since there is no regulation for the optimum position in the base station signal to provide the GAP at the compressed mode time, there occurred a problem that, when the BCH information is received via the P-CCPCH, reception efficiency is deteriorated depending on the GAP position to be decided.
Since the GAP position is decided without taking into consideration the correspondence with the BCH information block, there occurs a problem that a portion of the same information block is always dropped out due to influence of the compressed mode. Because of the dropout of this same information block, necessary terminal information cannot be obtained depending on the situation, and there arises a trouble that a serious error on the system develops in a position registration, and the telephone communication is cut off half-way.